Cricket side that's fifty for one (3)
I believe the answer is:
leg
'cricket side' is the definition.
(I've seen this before)
'fifty for one' is the wordplay.
'fifty' becomes 'l' (Roman numeral).
'for one' becomes 'eg' (both can mean 'for example').
'l'+'eg'='LEG'
'that's' is the link.
(Other definitions for leg that I've seen before include "Poultry portion" , "Support; cricket side" , "Section of journey; limb" , "Run < on" , "Projecting support for chair or table" .)